For low loss devices (high Q, low D) it is not uncommon to realize negative readings on an LCR meter / Impedance analyzer. Note that the negative reading is physically impossible (for passive components) and the following explanation is provided.

Normally, Keysight power supplies are delivered configured to deliver their full specs at the output terminals. In some application, where long lead lengths to the DUT are unavoidable, the regulation of the power supply at the DUT can be significan...

These oscilloscopes can perform math functions such as FFT, integration, and differentiation on any analog channel or even on another math function. But they cannot use channel 3 or 4 for XY mode, addition, subtraction, or multiplication.